Examine source code of Twitch Chat Expander

{
  "manifest_version": 2,
  "name": "Twitch Chat Expander",
  "version": "1.1",
  "description": "This Firefox extension enhances the Twitch chat experience by increasing the textarea row count from 1 to 3, allowing for easier message composition and better readability",
  "content_scripts": [
    {
      "matches": [
        "*://*.twitch.tv/*"
      ],
      "js": [
        "extension.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{dd59ca66-d121-4d8f-9f21-6262f15d3a2a}"
    }
  }
}